Parathyroidectomy (cont.)

James K. Bredenkamp, MD, FACS

Dr. Bredenkamp recieved his medical degree from the University of California, San Francisco School of Medicine. He then went on to serve a six year residency at the University of California, Los Angeles School of Medicine in the department of Surgery.

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

What causes hyperparathyroidism?

There are two types of hyperparathyroidism, primary and secondary. The most common disorder of the parathyroid glands and one that causes primary hyperparathyroidism, is a small, tumor called a parathyroid adenoma. A parathyroid adenoma is a benign condition in which one parathyroid gland increases in size and produces PTH in excess. (As opposed to parathyroid adenoma, it should be noted that malignant tumors of the parathyroid glands, that is, cancer, is very rare.) In most situations patients are unaware of the adenoma, and they are found when routine blood test results show an elevated blood calcium and PTH level. Less commonly, primary hyperparathyroidism may be caused by overactivity of all of the parathyroid glands, referred to as parathyroid hyperplasia.

With secondary hyperparathyroidism, the secretion of PTH is caused by a nonparathyroid disease, usually kidney failure.

When is a parathyroidectomy necessary and how is it performed?

Parathyroidectomy is necessary when calcium levels are elevated, if there is a complication of hyperparathyroidism (such as kidney stones, osteoporosis, or bone fractures), or if a patient is relatively young. Tests such as a high-resolution ultrasound or a nuclear medicine scan (called a sestamibi scan) help to direct the approach preoperatively or intra-operatively by identifying the location of the overactive, enlarged gland. During a parathyroidectomy, the surgeon delicately removes one or more of the tiny parathyroid glands. In some situations, both sides of the neck are explored, while in other cases a direct approach is made through a small incision (referred to as a minimally invasive parathyroidectomy). In rare situations, the offending gland cannot be found. (A portion of a gland also may be transplanted to another site in the neck or the arm to preserve parathyroid function.)

Whereas preoperative tests help to identify hyperparathyroidism and to direct the surgical approach, PTH levels obtained during parathyroidectiomy help to guarantee the successful resection of the abnormal gland by demonstrating a return of the PTH levels to normal after the suspected parathyroid adenoma is removed. Using this method, a PTH determination is obtained immediately prior to the resection and compared to a PTH determination done ten minutes after the resection.